Valve tappet



c. voORHlEs Feb. v3, 1942.

VALVE TAPPET original Filled June 4, 1934 TT ORNE K5.

Patented Feb. 3, 1942 UNITED STATES PATENT miaou OFFICE VALVE TAPPETOriginal application June 4, 1934, Serial No.

728,813. Divided and this application September 15, 1939, Serial No.295,104

This invention relates to automatic compensating tappets for operatingsuch parts as the intake or exhaust valves of internal combustionengines and more especially relates to mprovements in the constructionand arrangement of tappets of such character, and is a division of myapplication for Letters Patent of the United States forimprovements incompensating vhydraulic tappets for internal combustion engines,

tiled June 4, 1934, and serially numbered 728,813, issued April 8, 1941,as Patent Number 2,237,854.

The principal object of the invention is to provide an improvedautomatic compensating mechanism for tappets especially adapted foroperating movable parts of an. internal combustion engine.

Another object is to provide a novel plunger construction for hydrauliccompensating tappets which includes novel means for providing a sealbetween the plunger and the cylinder thereof.

Further objects of the invention include the provison of a tappet of thetype described including a cylinder and a plunger together with novelmeans for sealing the plunger to the cylinder?` and providing means foreifecting an automatic and positively controlled leak-down of theplunger in the cylinder; the provision of a lconstruction as abovedescribed in which the construction and arrangement of the seal and ofthe leakdown means eliminates the necessity for selective or otherexceedingly accurate t between theplunger and the cylinder; theprovision of a construction as above described in which the leak-downmeans is formed as a part of the sealing means; the provision of aconstruction as above described in which the sealing means includes aring of soft and ductilematerial arranged for continued expansion as thewear' of the same dictates in order to maintain the desired sealingcharacteristics thereof.

The above being among the objects of the present invention, the sameconsists in certain novel features of construction and combinationsoi'parts to be hereinafter described with reference to the accompanyingdrawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates suitable embodiments ofthe present invention and in which like numerals refer to like partsthroughout the several different views,

Fig. 1 is a viewpartly in section and partly in elevation of a fragmentof an internal combustion engine showing a valve tappet and cam in op-Fig. 4 is a cross-sectional view taken on the v line 4-4 of Fig. 3;

Fig. 5 is a view partly in elevation and partly in section similar toFig. 2, but showing a vmodied form of sealing means; I

Fig. 6 is a plan view of the modified form of a sealing ring shown inFig. 5;

Fig. '7 is a cross-sectional view line 1-1 of Fig. 6;

Fig. 8 is a plan view of the washer used in connection with thesealinggasket or ring shown in Fig. 5; and,

Fig. 9 is a cross-sectional view taken on the line 9-9 0f Fig. 8.

In the construction disclosed in Fig. 1, the valve I and cam 2 and theirarrangement and taken on the construction are conventional. 4Myimproveof oil is supplied to the tappet from the lubricatv ing system ofthe engine and the oil is introduced through a passage 4 into a chamberor conduit 5 provided in the engine block adjacent the tappet guide 6,said tappet guide forming a cover or closure for the pocket in theblock. If desired the pocket could be formed in the valve guide and aseparate cover provided therefor, as illustrated in Fig. 15 of my aboveidentied application of which the present is a division. A tube or pipe'I` is provided in the passage I and extends in adiagonal directionupwardly to a point adjacent the upper wall of the chamber 5, or thepassage 4 may lead into the upper part of the pocket and the pipeomitted. The chamber 5 is provided with a gas or air'outlet passage 8extending from its upper end through and near the upper end of thetappet guide 6. e The chamber 5 is also provided `with another passage 9leading from its lower portion into the bore of thel tappet guide 6, andthe tappet guide 6 is provided with a longitudinal groove I0 in itsintermediate portion through which oil may pass from the passage 9upwardly along the innerwall passage 4 and the tube 'I and spills out ofthe upperend of the tube into the chamber or conduit 5. This provisionof means for introducing the oil into the upper end of the chamber 5 andpermitting it to spill therein has the eiect of assisting in theseparation of gases or air included in the oil at the point of thedischarge of the oil from the tube 1. Aerated oil delivered at a pointhigh in chamber 5 will remain in upper portion of the chamber until theair is released therefrom. The gases or air naturally remain in theupper part of the settling chamber 5 and will pass outwardly through thepassage 3 into the tappetguide 6 and thence upwardly between the guideand the tappet to escape. Thus the oil in the bottom of .the settlingchamber 5, which is introduced through the passages 9 and l@ to thetappet, is substantially ree of entrapped air or gas which air or gasmakes the oil undesirably compressible if carried into the compressionchamber of the tappet, i. e., the presence of air or gas in the oilwhich is used to support the reciprocable plunger oi the tappet in itsadjusted positions, is very undesirable for the reason that it enablesthe supporting hydraulic column beneath the plunger to be compressed toa degree which seriously interferes with and sometimes actually preventsthe compensating function of the reciprocable plunger, and makes itimpossible to accurately regulate the time opening and lift of thevalves.

The tappet construction, as shown in Fig. 2, comprises a cylindricaltappet body I5 so'formed as to slidably flt in the guide sleeve 6 andprovided with an enlarged cam contacting head I6. The cylindrical bodyI5 is provided with an internal cylindrical bore, as shown, extendingsubstantially the full length of the body. Within this bore is slidablydisposed a plunger I 1, preferably n the form of a hollow tubethroughout its upper portion, and provided with a plug insert I8 at itsupper end which is adapted to close the upper end of the body and tocontact and support the end of the valve stem, as shown in Fig. 1. Thelower end of the plunger I1 is provided with a projection I9 of reduceddiameter. The lower end of this projection is provided with acylindrical bore which terminates short of the upper end of theprojection I9 and-which is connected with the internal bore of the mainbody I1 by a smaller passage 2|. The shoulderat 'the lower end of thissmaller passage 2| and the upper end of the bore 20 in projection I9provides a seat for a valve 22 shown by way of illustration as a ballvalve. AThe ball valve is rey tained in the bore 20 by means of thecross-pin 23 extending across the base 20 below the ball 22 and securedin the walls of the projection I9.`

At the junction of the plunger I1 with the reduced end I9 thereof abeveled shoulder 31 is formed, shown by way of illustration as disposedat an angle of approximately 45 with respect to the axis of the plunger,although this angle may be varied to obtain the desired effect of thesealing ring or gasket hereafter described. A sealing ring 35, shown indetail in Figs. 3 and 4, encircles the projection I9 and relativelyclosely ts the bore of the body I5 and is provided with a beveled upperface complementary to and which lits the beveled shoulder 31 of theplunger I1. A coiled spring 24 surrounds the projection I9 within thelower end of the bore of the main body portion I5 and bears at its upperend against the lower face of the sealing ring 35 and at its lower endagainst the bottom of the bore in the body portion I5. 'I'he lower endof the spring 24 is preferably slightly larger than the main bodyportion thereof and preferably is sulciently tightly received within thelower end of the bore of the body I5 to prevent its rotation therein.

The ring 35 is formed of metal which may Vbe lead or the like or othersuitable material and is split at 36 not only in order to permit it toexpand and contract radially in operation and also to provide a passagethrough which oil in the compression chamber under compression mayescape to provide a denite leak-down rate for the plunger l1 in the bodyI5 during operation, but also to allow air to be vented from thecompression chamber below the ball valve and well in the lower end olthe tappet body l5. Additionally, the co-operation of the inclined upperface of the packing ring 35 and inclined shoulder 31 of the plungerunder the force of the spring 24 and the high pressure of the oil in thepressure chamber acting on its lower face results in a wedging actionduring the compression stroke of the plunger which not only frictionallyresists the downward movement of the plunger in the body but alsoincreases the efficiency of the seal. As will be understood the width ofthe gap 36 in the sealing ring 35 controls the leak-down rate while theangle of the shoulder 31 primarily controls the desired pressure of thepacking ring upon the wall of the bore in the body I5, and these may bevaried to obtain any desired result.

The body I5 is provided with an annular groove or recessed portion 28around its intermediate portion and with oppositely disposed passages 29which lead from the upper portion of this recess to the interior of theltappet body. The plunger I1 is provided with an annular recess 30 in itsintermediate portion and with passages 3| leading from the recess 30 tothe hollow'nterior of the plunger. Oil is introduced into the plungerthrough the recess 28, passage 29, recess 30 and passage 3|, Where itfalls to the bottom of the plunger against the ball valve 22 and as theplunger is raised relative to the tappet body I5 and the pressurerelieved beneath the ball 22, the oil will flow down past the ball intothe lower part of the tappet body I5 and into the compression chamberthere provided between the end of the plunger and the tappet body. It isdesirable that the plunger I1 does not follow up a stuck valve I too farand to this end, the groove 30 may be of only suiiicient width to allowfor the desired adjustment of the tappet and shuts olf the supply of oilwhen the plunger moves in excess of the amount necessary for normaladjustment. The spring 24 is compressed from free length only the amountrequired for adjustment thus causing the plunger to follow up a stuckvalve only a limited distance.

During the operation of the engine some of the oil in the compressionchamber in the lower part of the tappet will leak outwardly through thegap 36 in the sealing ring 35 and then upwardly between the plunger andthe tappet body, and as this occurs the leakage will be replaced throughthe ball valve 22 by the oil in the upper portion of the plunger. Thespring 24 acts constantly during the intervals when the valve l is onits scat to force the plunger I 1 upwardly against the valve stem toeliminate any clearance between the two, and any movement of the plungerI1 outwardly of the tappet body I5 will reduce the pressure in thechamber or space between the end of the plunger and the end of the borein the tappet body and so permit the ball valve 22 to fall away from itsseat by its own weight and adchamber beneath mit suiiicient oil intothe' compression chamber beneath the plunger to maintain the plunger inits adjusted position.

- from the During operation. the hollow interionof the '.vides aconstant reservoir of oil which is immediately available for inductioninto the compression chamber beneath the plunger upon the starting ofthevengine sothat ,thev automatic adjustment may be immediately obtainedupon starting even though the engine has not been running for aconsiderable time.

In the modification shown in Figs. 5, 6, "l, 8 vand 9 I have provided aseal of slightly diierent kind than that shown in Figs. 2, 3 and 4.'I'he packing ring 38 here shown is of an impressible or compressiblematerial. It is not split or divided and may be of lead or othersuitable metal of relatively high ductility. It is retained in place bymeans of a metal washer 3 9 which bears against its underside and is inturn supported by the upper end of the coil spring. This type of packingring tends to pack and be expanded between the plunger and the tappetbody by the pressure of the spring 24 and the oil in the pressurechamber and to become more -dense with use and consequently provide amore effective seal. The angle 31 between the sealing ring 38 andtheplunger may be variedto regulate the wall pressure of the ring and theleak-down rate on this type of lifterv is made substantially` constantby providing a small opening l through the wall of the tappet body justbelow the ring 38. This openingis masked by the tappet guide.

Formal changes may be made in the specific embodiment of theA invention'described without departing from the spirit and substance'of the broadinvention, the scope of which is'jcommensurate with the appended claims.

What is claimed is:

1. A hydraulic valve tappet comprising, in combination,- a cylindricalbody provided with a longitudinal bore, said body being closed at oneend and open at the other, a plunger disposed in said bore and inconjunction with said cylindrical body defining the hydraulic'compression chamber between the plunger and the closed end of saidlcylindrical body, said cylindrical body adapted to receive a liquidtherein, means providing for relatively free flow of said liquid pastsaid plunger in said bore in one direction only, and resilient means forextending said plunger outwardly with respect to said cylindrical body,means including a Washer-like element of ductile metal providing a sealbetween the plunger and cylindrical body for-substantially preventingiiow of liquid out of said hydraulic compression chamber and meansproviding for a definite and predetermined escapement of liquid out ofsaid hydraulic compression chamber.

2. A valve tappet comprising a cylinder having a fluid reservoirtherein, a plunger slidably the cylinder walls to reservoir past theplunger in one direction, and means providing for the relatively freeilow of. iiuid past said plunger in the opposite direction, to saidreservoir.

3. A valve tappet comprising a cylinder having a fluid reservoirat oneend, a plunger havingla body portion slidably engageable with thecylinder walls, a seal comprising a member movable with the plunger andpositioned at the end ofthe plunger body adjacent the reservoir, saidmember having a circular outer edge portion of ductile metal slidablyengaging the cylinder walls throughout the circumference thereof toprevent the to the space between the cylinder walls and plunger body,and means providing a vb'y-pass vthrough the member to the space betweenthe cylinder walls and plunger body.

4. A valve tappet comprising a cylinder having a reservoir therein, aplunger having a body slidably engaging the side walls of the cylinder,a seal comprising .a member positioned at the end of the plunger bodyadjacent the reservoir and movable with the plunger, said member havinga circular edge portion engageable with the cylinder wall throughout thecircumference thereof and'being formed of a metal possessing theductility required to provide for spreading of the member under theaction of pressure applied to the member in the general direction of e ythe plunger to intimately engage the circular edge of the member withthe cylinder walls, and

means providing for the relatively free iiow of liquid in said cylinderpast said plunger in one direction only.

5. A valve tappet comprising a cylinder having a iluid'reservoirtherein, a plunger having a body portion slidably engageable with thecylindergwalls, a seal positioned at the end of the plungeradjacent thevreservoir and movable with the plunger, said seal comprising a memberof ductile metal having a circular outer edge frictionally engaging thecylinder walls andengaged between axially spaced and relatively `axiallymovable parts of rigid metal wherebyto be responsive to the applicationof pressure on the member in thel general direction'of movement of theplunger to effect spreading of the'member and insure a continuouscircumferential engagement of the outer circular edge of the member withthe cylinder walls, and means associto' be expanded into contact withthe wall of said bore when said tappet is subjected to com- 'mounted inthe cylinder for movementvtoward I ated with said plunger providing forthe relatively free flow of liquid into said cylinder past said plungerin one direction only.

6. A valve tappet comprising, in combination, a body provided with alongitudinal bore, said bodyy being closed at one yend and open at theother, a plunger disposed in said bore, resilient means cooperatingvbetween said body and plunger normally urging said plunger outwardly ofsaid bore whereby to increase the effective length of said tappet, meansincluding a yieldable element of ductile metal carried by said plungerso constructed and arranged as to tend pressive forces tending toshorten it, means providing for the substantially free iiow of liquid insaid bore past'said plunger to the space between said plunger and theclosed end of said bore, and

means providing fora limited escape of liquid?" from the space betweensaid plunger and the closed end of said bore.

'1.-A hydraulic valve tappet comprising, in

resist the escape o! tiuid escape. of iiuid from the reservoirlcombination, a body provided with a blind bore therein adapted toreceive a liquid, a plunger disposed in said bore defining a hydrauliccompression chamber in said body between its inner end and the closedend of said bore, resilient means cooperating' between said body andplunger for urging said plunger outwardly of said borel means providingfor relatively free it, and means providing for a limited escape of yliquid from said compression chamber.

8. A hydraulic valve tappet comprising, in combination, a body providedwith a blind bore therein adapted to receive la liquid, a plungerdisposed in said bore defining a. hydraulic compression chamber in saidbody between its inner end and the closed end of said bore, resilientmeans cooperating between said body and plunger for urging said plungeroutwardly of said bore, means providing for relatively free ow of liquidin said bore past said plunger to said compression chamber, meansincluding a yieldable but substantially incompressible element composedof highly ductile metal substantially conilned by said plunger, saidhydraulic compression chamber and said body for causing a lagging orretardation in movement of said plunger relative to said body during theapplication of compressive forces'acting on said tappet and tending toshorten it, and means providing for a limited escape of liquid from saidcompression chamber.

CARL VOORHIES.

